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Commit 2e52f4fe authored by dingtianhong's avatar dingtianhong Committed by David S. Miller
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bonding: rebuild the lock use for bond_loadbalance_arp_mon() 



The bond_loadbalance_arp_mon() use the bond lock to protect the
bond slave list, it is no effect, so I could use RTNL or RCU to
replace it, considering the performance impact, the RCU is more
better here, so the bond lock replace with the RCU.

The bond_select_active_slave() need RTNL and curr_slave_lock
together, but there is no RTNL lock here, so add a rtnl_rtylock.

Suggested-by: default avatarJay Vosburgh <fubar@us.ibm.com>
Suggested-by: default avatarVeaceslav Falico <vfalico@redhat.com>
Signed-off-by: default avatarDing Tianhong <dingtianhong@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 733ab639

drivers/net/bonding/bond_main.c

+12 −6
Original line number Diff line number Diff line
@@ -2411,12 +2411,12 @@ void bond_loadbalance_arp_mon(struct work_struct *work) 
	struct list_head *iter;

	int do_failover = 0;



	read_lock(&bond->lock);



	if (!bond_has_slaves(bond))

		goto re_arm;



	oldcurrent = bond->curr_active_slave;

	rcu_read_lock();



	oldcurrent = ACCESS_ONCE(bond->curr_active_slave);

	/* see if any of the previous devices are up now (i.e. they have

	 * xmt and rcv traffic). the curr_active_slave does not come into

	 * the picture unless it is null. also, slave->jiffies is not needed
@@ -2425,7 +2425,7 @@ void bond_loadbalance_arp_mon(struct work_struct *work) 
	 * TODO: what about up/down delay in arp mode? it wasn't here before

	 *       so it can wait

	 */

	bond_for_each_slave(bond, slave, iter) {

	bond_for_each_slave_rcu(bond, slave, iter) {

		unsigned long trans_start = dev_trans_start(slave->dev);



		if (slave->link != BOND_LINK_UP) {
@@ -2487,7 +2487,14 @@ void bond_loadbalance_arp_mon(struct work_struct *work) 
			bond_arp_send_all(bond, slave);

	}



	rcu_read_unlock();



	if (do_failover) {

		/* the bond_select_active_slave must hold RTNL

		 * and curr_slave_lock for write.

		 */

		if (!rtnl_trylock())

			goto re_arm;

		block_netpoll_tx();

		write_lock_bh(&bond->curr_slave_lock);
@@ -2495,14 +2502,13 @@ void bond_loadbalance_arp_mon(struct work_struct *work) 


		write_unlock_bh(&bond->curr_slave_lock);

		unblock_netpoll_tx();

		rtnl_unlock();

	}



re_arm:

	if (bond->params.arp_interval)

		queue_delayed_work(bond->wq, &bond->arp_work,

				   msecs_to_jiffies(bond->params.arp_interval));



	read_unlock(&bond->lock);

}



/*